Axle Shock-load absorber and Guard

ABSTRACT

A device for reducing axle failures on motorized vehicles that includes a sleeve that wraps around the axle and a separate single pieces or two-piece axle guard that wraps around said sleeve. The present invention allows the torsional flex that the axle manufacturer intended to occur but prohibits the axle from bending and possibly breaking. The present invention also acts as a shock-absorber for the axle by absorbing energy that is being transferred through the axle during normal use. Absorbing this energy increases the life of the axle and drive-train and reduces the risk of failure during use.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application61/724,978.

BACKGROUND OF THE INVENTION

During the use of motorized vehicles, such as all-terrain-vehicles(ATVs), utility-terrain-vehicles (UTVs), and other off-road typevehicles, it is known for there to be axle failures in the form ofbending and/or breaking. This can render the vehicle inoperable and theoperator stranded, potentially in remote, hard to reach areas. A commonresponse to these bending or break failures is to replace the originalmanufacturers intended axle with a larger more rigid after-market axle.While this does reduce the chance of axle failure, because it is nolonger the weakest link, failures can shift to other components in thedrive-train assembly; for example, CV joints and the differential. Thisis often a more serious and costly failure and is a main reason thataxles are normally designed to fail first. Furthermore, in the eventthat a break in the axle shaft does occur, it typically will leave thevehicle inoperable.

Axle shafts are designed to provide a certain amount of torsional flex.A common, known, approach is to decrease the axle shaft diameter toachieve the desired amount of torsional flex the axle will have for agiven applied torque. The function that the torsional flex provides ismulti-fold. It decreases the impact to other driveline components duringhigh torque loads that frequently occur during use. It improves fatiguelife by absorbing torsional forces and requiring less strain from theaxle's material properties. The axle shaft acts as a ‘release valve’ andis typically designed to fail before other components in the drivetrainsystem. The benefit this serves is offset by an increased proneness toaxle bending and breaking due to force shock loads that occur duringuse. The proposed device inhibits axle bending and absorbs energy, alsoreferred to as shock-load, while allowing the intended torsional flex inthe axle shaft to occur, decreasing the chance of failure and extendingthe life of the axle. Furthermore, in the event that the axle breakswith the proposed device attached, assuming other drive axles are stilldelivering power to the ground, the vehicle will remain operable.

Having researched and found no prior-art, the inventors sought to inventa device to reduce the frequency of these failure occurrences while atthe same time preserving the intended function of the originalmanufacturer's designed-in torsional flex capabilities of the axle.

BRIEF SUMMARY OF THE INVENTION

A device for reducing the occurrence of axle bending or breaking on anymotorized, powered vehicle such as, but not limited to,all-terrain-vehicles (ATV's), utility-terrain-vehicles (UTV), andoff-road vehicles. In summarized form, when the proposed device isattached to an axle shaft it prevents the axle from bending and absorbsshock load that is being transferred through the axle during normal use,while allowing the original axle manufacturer's intended torsional flexin the axle shaft to occur, decreasing the chance of failure andextending the life of the axle. Furthermore, in the event that the axlebreaks due to excessive torsional flex, with the proposed deviceattached, assuming other drive axles are still delivering power to theground, the vehicle will remain operable.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1: Isometric exploded assembly view of first embodiment of presentinvention.

FIG. 1-1: Sleeve slit down the length that snaps over an axle shaft.

FIG. 1-2: Axle guard halves that are clamped around sleeve (FIG. 1-1).

FIG. 1-3: Socket head cap screws used to clamp axle guard halves (FIG.1-2) around sleeve (FIG. 1-1).

FIG. 1-4: Dowel pin for aligning axle guard halves together (FIG. 1-2).

FIG. 2: Isometric exploded assembly view of first embodiment of proposedinvention showing sleeve (FIG. 1-1) around an axle shaft.

FIG. 2-1: Axle shaft.

FIG. 3: Detailed elevation views of first embodiment with optional coredout material (FIG. 3-1) for weight reduction.

FIG. 4: Elevation views of alternative embodiment showing one pieceversion as opposed to two axle guard halves referenced in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

It will be apparent to those skilled in the art, that is, to those whohave knowledge or experience in this area of technology, that manydesign variations are possible to achieve the stated use and benefits ofthe present invention. The following detailed discussion of variousalternative and preferred embodiments illustrate the general principlesof the invention with reference to several specific embodiments of thepresent invention.

FIG. 1 illustrates the preferred embodiment of the present invention.The sleeve (FIG. 1-1) is a tubular component that may be extruded ormachined from solid stock, is not limited to, but in its preferredembodiment, is manufactured out of a polymeric material such as nylon,with a slit down its length so that it can be spread and snapped onto anaxle shaft. After the sleeve (FIG. 1-1) is snapped over an axle (FIG.2-1) the two axle guard halves (FIG. 1-2) are clamped around the sleeveusing the dowels (FIG. 1-4) for alignment and the socket head cap screws(FIG. 1-3) to clamp the axle guard halves onto the sleeve. The axleguard halves may be cast, extruded, molded, or as in the presentinvention, machined out of, but not limited to, billet aluminum. The fitbetween the axle guard halves and the sleeve as designed is aninterference fit which is to say that the inner diameter of the axleguard halves is smaller than the outer diameter of the sleeve, and whenclamped together this allows for positive and direct transfer of energyfrom the axle, into the sleeve, and subsequently the energy is absorbedand dissipated into the axle guard halves. In its preferred embodiment,the sleeve is a material with a low friction coefficient allowing theaxle to operate as the original manufacturer intended. That is to say,the designed-in torsional flex characteristics of the axle is stillallowed to occur because the axle can still twist. By absorbing anddissipating energy, the present invention, protects the drive-train ofthe vehicle by giving the energy a place to travel to other than thedrive-train consisting of, but not limited to, axles, joints, anddifferentials. The present invention when assembled to the axle preventsthe axle from bending. Axle bending is another failure mode that causesaxle failure from repeated bending causing material fatigue or a singlesignificant bend causing immediate axle breakage.

FIG. 3 illustrates a version of the present invention where material iscored (FIG. 3-1) out of the axle guard halves as a means to reduceweight. These cored out features could be created by, but not limitedto, machining, casting, and molding.

FIG. 4 illustrates an alternative embodiment of the present inventionwhere a single piece axle guard replaces the two axle guard halves (FIG.1-2). The sleeve (FIGS. 1-1, 4-2) is a tubular component that may beextruded or machined from solid stock, is not limited to, but in itspreferred embodiment, is manufactured out of a polymeric material likeNylon, with a slit down its length so that it can be spread and snappedonto an axle shaft. After the sleeve (FIG. 4-2) is snapped over an axle(FIG. 4-1) the single axle guard (FIG. 4-3) is slid over the sleeveusing an arbor press or equivalent assembly machine to press the axleguard over the sleeve in an interference condition as described in thefirst embodiment of the present invention. The axle guard can be cast,extruded, molded, or as in the present invention, machined out of, butnot limited to, billet aluminum. An alternative method is injectionmolding the guard out of a polymer in an over-molding process that willmold the net shape guard over the sleeve eliminating the need toassemble the guard over the sleeve.

The invention claimed is:
 1. A device that absorbs energy beingtransferred through an axle during use.
 2. A device that in the event ofan axle break caused by excessive torsional flex will allow the vehicleto remain operable.
 3. A device that prevents the axle from bendinge. 4.A device that prevents the axle from bending without preventing theintended torsional-flex of the axle to occur.
 5. A device consisting ofa tubular sleeve (FIG. 1-1) that may be made out of, but not limited to,a polymeric or rubber material, and is slit down the length or splitinto two halves. Alternatively, the tubular sleeve can be created bymolding or casting a polymeric, rubber, or metal material directlyaround the axle.
 6. The device of claim 4 where said sleeve isencapsulated by two axle guard halves (FIG. 1-2) made out of, but notlimited to, aluminum , steel, thermoplastic polymer, thermoset polymer,or rubber. Alternatively, the axle guard can be a single piece version(FIG. 4-3).
 7. The device of claim 4 where said housing halves have finsor cored out sections (FIG. 3-1) along the main body for weightreduction.
 8. The device of claim 5 where said housing halves areaffixed to each other by means of screws (FIG. 1-3).
 9. The device ofclaim 5 where said housing halves consist of mating holes containingdowel pins (FIG. 1-4).
 10. The device of claim 5 where the single axleguard version (FIG. 4-3) is pressed onto the sleeve (FIG. 4-2) along thelongitudinal length of the sleeve.
 11. The device of claim 5 where thesingle axle guard version (FIG. 4-3) is molded onto the sleeve (FIG.4-2).